JP2006222059A - Flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide flat cables which are soft, superior in flexibility, which can be passed through an extremely small through-hole, which can maintain precision of pitch between coaxial cables at a favorable level and which can easily and surely carry out complicated and troublesome connections. <P>SOLUTION: The flat cables 101 and 102 are characterized in that the external diameter of the coaxial cables 10 is 0.15 to 0.35 mm, at least a portion of the outer circumference of each coaxial cable 10 is fastened to a laminated sheet 50 composed of porous polytetrafluoroethylene (EPTFE), and the flat cables are constructed so that these flat cables can pass via the through-hole with an internal diameter of 2.0 to 5.5 mm. As a result, in the flat cables 101 and 102, since a plurality of coaxial cables 10 are fastened to one or more laminated sheets 50 composed of EPTFE, these flat cables are superior in terms of softness and flexibility and can be passed through even the extremely small through-hole while maintaining the precision of the pitch between the coaxial cables at a favorable level, by folding or rolling up the flat cables in the direction of length. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flat cable in which ultrafine coaxial cables for high-speed transmission are arranged in parallel.

  A coaxial cable is generally known in which a central conductor is covered with a dielectric, the outer periphery of the dielectric is covered with a shield layer made of a conductor, and the outer periphery of the shield layer is covered with a jacket (jacket). It is widely used as a transmission line for high frequency. In recent years, the diameter of the coaxial cable has been reduced, and for example, a very thin coaxial cable having a central conductor diameter of 0.1 mm or less and an outer diameter of the coaxial cable of about 0.35 mm has become a small-sized notebook personal computer or mobile phone. It is used for electronic devices such as telephones.

  In these electronic devices, for example, a plurality of coaxial cables are used to electrically connect a liquid crystal display unit and a main body of a notebook personal computer via a hinge having a small diameter. It is complicated. As a means for easily and reliably performing such complicated connection, there is a flat cable configured by holding a plurality of coaxial cables in parallel on the same plane. For example, Patent Document 1 discloses an example of this flat cable. Is described. However, in this Patent Document 1, it is difficult to accurately maintain the pitch interval formed between the coaxial cables of the flat cable when the cable end processing is performed after the flat cable passes through the thin-diameter hinge. There is a problem that the terminal processing becomes troublesome.

In addition, a woven cable woven using a plurality of coaxial cables may be used for electrical connection between a liquid crystal display unit and a main body unit, for example, in a mobile phone, etc. When the terminal processing of the cable is performed after the woven cable passes through the thin-diameter hinge, it is difficult to accurately maintain the pitch interval formed between the cables, and the terminal processing becomes troublesome.
JP 2004-273333 A

  In mobile phones (hereinafter referred to as “terminals”), terminals are becoming smaller, lighter, and more advanced, and complicated wiring and connections are made inside terminals, despite limited space. It has been demanded. Further, as a form of the terminal, in addition to the so-called folding type in which the movable part on which the liquid crystal display unit is formed rotates and opens and closes with respect to the main body part, the movable part is attached to the main body part to be rotatable in addition to folding. A new type of terminal has recently appeared.

  In the above foldable / rotary terminal, the movable portion and the main body are connected via the cylindrical hinge having the thin diameter as described above, and the liquid crystal display and the main body are flat. A cable or a woven cable is passed through the hinge hole of the hinge to make an electrical connection. As described above, a flat cable or a woven cable has been used in the terminal, and the flat cable or the woven cable described in Patent Document 1 is connected to the liquid crystal display unit via a cylindrical hinge having a small diameter. When electrically connecting the main body and the main body, the cable end processing for keeping the pitch interval of the coaxial cable in the flat cable or the woven cable constant and accurate before passing through the hinge, for example, each coaxial cable is connected to the connector terminal Alternatively, if terminal processing for connecting to an FPC (Flexible Printed Circuit) is not performed, it is difficult to accurately maintain the pitch interval after inserting the cable hinge, and before passing the hinge to accurately maintain the pitch interval. If terminal processing is applied to the terminal, the diameter of the terminal processing section will increase, allowing the hinge to pass The problem of becoming impossible arises. However, in the future, it is expected that the types of terminals will be further diversified into various types. On the other hand, considering that the terminal will be further reduced in size, weight, and functionality, it will be complicated and troublesome. The appearance of a flat cable that can easily and reliably perform electrical connection and a flat cable that can ensure a uniform pitch between coaxial cables is desired.

  The present invention has been made in view of the various problems as described above, and an object of the present invention is to be soft, excellent in flexibility, pass through a very narrow through hole, and improve the pitch accuracy between coaxial cables. An object of the present invention is to provide a flat cable that can be held well and can easily and reliably perform complicated and troublesome connections.

  To achieve the above object, the flat cable according to claim 1 is a flat cable configured by arranging a plurality of coaxial cables in parallel, and the outer diameter of the coaxial cable is 0.15 to 0.35 mm. At least a part of the outer periphery of the coaxial cable is fixed to a laminate sheet made of porous polytetrafluoroethylene having a fusion layer, and configured to be able to pass through a through hole having an inner diameter of 2.0 to 5.5 mm. It is a feature.

  Thereby, the flat cable according to claim 1 is excellent in flexibility and flexibility because a plurality of coaxial cables are fixed to a laminate sheet made of porous polytetrafluoroethylene having a fusion layer. While maintaining good pitch accuracy between coaxial cables, it is possible to pass through extremely small through-holes by bending or rounding flat cables in the long direction, making complicated and troublesome electrical connections easy and reliable. It can be carried out. As a result, the flat cable of the present invention can be passed through the hinge hole of the portable telephone, and can be used for connection of the portable telephone.

  In addition to the above, the flat cable according to claim 2 is characterized in that at least 20 coaxial cables are included. As a result, the flat cable according to claim 2 can be passed through extremely small through-holes while maintaining good pitch accuracy between the coaxial cables by bending or rounding. It is possible to cope with even an electronic device that requires the above.

  In addition to the above, the flat cable according to claim 3 is characterized in that the thickness of the laminate sheet is 30 to 150 μm. As a result, the flat cable according to claim 3 is excellent in flexibility and flexibility and also in durability.

  The flat cable according to claim 4 is further characterized in that the fusion layer is made of a tetrafluoroethylene / hexafluoropropylene copolymer. As a result, the flat cable according to claim 4 can fix the coaxial cable to the laminate sheet by thermal fusion, and further, after the fusion fixation, a part of the laminate sheet is subjected to laser processing. It is also possible to peel the part.

  Hereinafter, embodiments of the flat cable according to the present invention will be described. The embodiments described below do not limit the invention according to the claims, and all the combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent.

  First, a representative embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a coaxial cable 10 and a laminate sheet 50 constituting a flat cable according to the present invention. FIG. 2 is a cross-sectional view showing the flat cables 101 and 102 according to the present invention. FIG. 3 is a cross-sectional view showing a state where the flat cable is bent and a state where the flat cable is rounded.

  As shown in FIGS. 2A and 2B, the flat cables 101 and 102 according to the present invention are fixed by laminating a plurality of ultra-thin coaxial cables 10 arranged in parallel and at equal intervals with a laminate sheet 50. Composed. First, the coaxial cable 10 and the laminate sheet 50 constituting the flat cables 101 and 102 according to the present invention will be described with reference to FIG.

  FIG. 1A is a cross-sectional view showing a cross-section of the coaxial cable 10 (the direction in which the coaxial cable 10 extends is taken as the axial direction and cut along a plane perpendicular to the axial direction). The coaxial cable 10 is formed by forming a dielectric layer 12 made of an insulating material around a center conductor 11 formed by twisting a plurality of (for example, seven) conductors (for example, a diameter of about 20 μm). A plurality of conductors are horizontally wound around the outer periphery of the layer 12 to form a shield layer 13, and an outer cover 14 made of an insulating material is formed around the outer periphery of the shield layer 13. The coaxial cable 10 is a cable that can be used to connect the liquid crystal display unit and the main body of the mobile phone described above. For example, the coaxial cable 10 has an extremely thin diameter of about 0.15 to 0.3 mm. It has become. In the present embodiment, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (hereinafter referred to as “PFA”) is used as a material for the dielectric layer 12 and the jacket 14.

  FIG. 1B is a perspective view showing a laminate sheet 50, and FIG. 1C is a cross-sectional view thereof (a view taken along line XX in FIG. 1B). As shown in FIG. 1C, the laminate sheet 50 has a two-layer structure of a base layer 51 and a fusion layer 52. The base layer 51 is an ultrathin sheet obtained by processing porous polytetrafluoroethylene (hereinafter referred to as “EPTFE”) into a strip shape having a thickness of 30 to 100 μm. EPTFE is a fluororesin that can be obtained by stretching a raw material polytetrafluoroethylene (hereinafter referred to as “PTFE”) and has a fine continuous porous structure. EPTFE has excellent properties such as heat resistance, chemical resistance, and weather resistance, and is excellent in durability even when processed into an ultrathin sheet having a thickness of 30 to 100 μm. Very good.

  The fusion layer 52 is formed on the side of the base layer 51 where the coaxial cable 10 is fixed, and is made of a tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter referred to as “FEP”) having a thickness of about 10 to 50 μm. Is a layer. The fusion layer 52 made of FEP can easily fuse and fix the jacket 14 made of PFA (coaxial cable 10) and the base layer 51 made of EPTFE (laminate sheet 50) by heat fusion. It is. In addition, by fixing by heat sealing, a part of the laminate sheet 50 can be subjected to laser processing after being fixed, and the part can be peeled off.

  In the flat cable 101 according to the present invention shown in FIG. 2A, the coaxial cable 10 described above is parallel and the distance between the coaxial cables 10 (hereinafter referred to as “cable pitch”) is, for example, 0.4 mm. A plurality of the laminated sheets 50 are arranged so that the laminated sheet 50 is disposed on the coaxial cables 10 and 10 so that the fusion layer 52 is on the coaxial cable 10 side, and the coaxial cables 10 and 10 are fused. It is a fixed flat cable.

  A flat cable 102 shown in FIG. 2 (B) is a flat cable in which the flat cable 101 is similarly fused and fixed from below the coaxial cables 10 and 10 with a laminate sheet 50. That is, the flat cable 102 has a double-sided laminated structure in which the coaxial cables 10 and 10 are sandwiched between two laminated sheets 50 and 50 (in contrast, the structure of the flat cable 101 is referred to as a “single-sided laminated structure”). Have.

  As described above, the flat cable according to the present invention may have either a double-sided laminated structure in which a plurality of coaxial cables 10 are sandwiched from both sides, or a single-sided laminated structure provided only on one side, and the use of the flat cable is taken into consideration. Any selection is possible.

In the flat cables 101 and 102 according to the present embodiment, the number of the coaxial cables 10 fixed by the laminate sheet 50 is not particularly limited. For example, although a flat cable composed of about 20 to 50 coaxial cables is used in a portable telephone, it may be about 500 to 600. Also, the cable pitch is not limited to 0.4 mm, for example, but can be set to a preferable cable pitch in consideration of the use of a flat cable.
As described above, in the flat cables 101 and 102 according to this embodiment, the micro coaxial cables 10 having an outer diameter of about 0.2 to 0.3 mm are arranged in parallel on the same plane, and the laminate sheet 50 made of EPTFE is used. Since it is fixed by heat fusion, the flat cables 101 and 102 maintain a predetermined cable pitch without disturbing the coaxial cables 10 while maintaining good flexibility. In particular, the flat cable 101 having a single-sided laminate structure has a high degree of freedom in its formability, and as shown in FIG. 3A, the flat cable 101 is bent in the axial direction, or as shown in FIG. Thus, it is easy to round the flat cable 101 in the axial direction. Note that in the flat cable 101 shown in FIGS. 3A and 3B, the laminate sheet 50 is used to protect the plurality of fixed coaxial cables 10 and prevent the coaxial cables 10 from being separated. A plurality of coaxial cables 10 are encased. Thus, the bent flat cable 101 and the rounded flat cable 101 can pass through, for example, a hinge hole 80a (through hole) (see FIG. 6A) formed in the hinge 80. .

  On the other hand, the above-described foldable and rotary portable telephones use a hinge having a hinge hole (through hole) having an inner diameter of 3.0 to 5.5 mm and a depth of 5 to 20 mm. Then, a hinge in which a hinge hole having an inner diameter of 3.0 to 4.0 mm and a depth of about 5 to 20 mm is used, and the inner diameter is expected to be reduced to about 2.0 to 3.0 mm. As described above, it has been difficult to pass a conventional flat cable through such a small hinge hole. However, according to the present invention, by arranging the ultra-thin coaxial cables 10 in parallel and fusion-fixing with the laminate sheet 50 made of EPTFE, the form can be easily changed while maintaining good flexibility. It became possible to provide a possible flat cable. Thereby, even a very small through hole formed in a hinge used for a rotary portable phone or the like can pass the flat cable according to the present invention. It has become possible to use the flat cable according to the present invention.

  Next, the terminal structure of the flat cable 101 according to the present embodiment will be described. 4 and 5 are plan views showing an example of a terminal structure at one end of the flat cable 101. FIG. FIG. 4A is a plan view of the flat cable 101 not subjected to terminal processing as viewed from the laminate sheet 50 side. A plurality of coaxial cables 10 are fused and fixed in parallel to the back side of the laminate sheet 50 shown in FIG.

  The flat cable 101b shown in FIG. 4 (B) was fixed by the laminate sheets 50a and 50b by peeling a part of the laminate sheet 50 by laser processing so as to leave the central laminate sheet 50a and the laminate sheet 50b at the end. The outer sheath 14 of the plurality of coaxial cables 10 is removed by laser processing. As shown in FIG. 4B, the coaxial cable 10 from which the jacket 14 has been removed has the shield layer 13 exposed.

  In the flat cable 101c shown in FIG. 4C, the flat cable 101b is subjected to a process of removing a part of the shield layer 13 to expose the dielectric layer 12 of the coaxial cable 10 (hereinafter referred to as “shield cut”). It is added.

  As described above, it is possible to perform various terminal processing on the flat cable 101 according to the present embodiment to improve the use and function. In particular, since the flat sheets 101b and 101c have the laminate sheet 50b at the end fixed to the coaxial cable 10, the pitch accuracy at the tip of the coaxial cable 10 can be satisfactorily maintained when passing through a hinge or the like. FIG. 5 shows an example of the terminal structure, and the terminal structure of the flat cable according to the present invention is not limited to these.

  Next, a usage pattern of the flat cable 101 according to the present embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a plan view showing an example of a usage pattern of the flat cable 101c. FIG. 6 is a plan view showing a state in which the flat cable 101 c 1 is passed through the hinge 80.

  As shown in FIG. 5A, a cut is formed by laser processing at an arbitrary position of the laminate sheet 50a left in the center of the flat cable 101c, and a part of the laminate sheet 50a is peeled off along the cut. (See FIG. 5B). At this time, as shown in FIG. 5C, the belt-like laminate sheet 50f may be left at an arbitrary position.

  FIG. 6A shows a state where one end of the flat cable 101c1 is passed through a through hole 80a formed in the hinge 80 in a bent or rounded state. As described above, the laminate sheet 50 is formed of EPTFE, and is excellent in flexibility and flexibility. Therefore, by bending or rounding the tip of the flat cable 101c1, the small sheet formed on the hinge or the like of the terminal. Even if it is the through-hole 80a, it is possible to let the front-end | tip of a flat cable pass. After the leading end of the flat cable 101c1 is passed through the hinge 80, the leading end may be expanded again as shown in FIG. As described above, since the coaxial cable 10 is fixed to the end portion of the flat cable 101c1 by the laminate sheet 50b, the flat cable 101c1 can be easily and reliably connected, and the pitch accuracy between the coaxial cables 10 is improved. It is possible to hold.

  Next, examples of the present invention will be described. A hinge passing test was performed using the flat cables 105, 106, 107, 108, and 109 of Examples 1 to 5 described below.

[Example 1] Flat cable 105
A dielectric layer made of PFA having a thickness of about 40 μm is provided on the outer periphery of a central conductor in which seven conductors having a diameter of 25 μm are twisted, and a conductor wire having a diameter of 30 μm is wound around the outer periphery of the dielectric layer to form an external conductor layer. EPTFE is formed so that the outer conductor layer is provided with a jacket of about 30 μm thickness on the outer periphery of the outer conductor layer, 40 ultra-fine coaxial cables having an outer diameter of 0.28 mm, and a cable pitch of 0.4 mm. A flat cable 105 was prepared by fixing only one side of the laminate sheet having a thickness of 80 μm.

[Example 2] Flat cable 106
A dielectric layer made of PFA having a thickness of about 35 μm is provided on the outer periphery of a central conductor in which seven conductors having a diameter of 20 μm are twisted, and a conductor wire having a diameter of 30 μm is wound around the outer periphery of the dielectric layer to form an external conductor layer. EPTFE so that the outer conductor layer has an outer conductor layer with an outer sheath of about 25 μm thickness and 40 ultra-fine coaxial cables with an outer diameter of 0.24 mm and a cable pitch of 0.3 mm. A flat cable 106 was prepared by fixing only one side of the laminate sheet having a thickness of 80 μm.

[Example 3] Flat cable 107
A dielectric layer made of PFA having a thickness of about 30 μm is provided on the outer periphery of a central conductor in which seven conductors having a diameter of 16 μm are twisted, and a conductor wire having a diameter of 20 μm is wound around the outer periphery of the dielectric layer to form an external conductor layer. EPTFE is formed so that the outer conductor layer is provided with a jacket of about 20 μm thickness on the outer periphery of the outer conductor layer, 40 ultra-fine coaxial cables having an outer diameter of 0.19 mm, and a cable pitch of 0.3 mm. A flat cable 107 was prepared by fixing only one side of the laminate sheet having a thickness of 80 μm.

  All of the flat cables 105, 106, and 107 described above are provided with a hinge having a through hole having an inner diameter of 3.0 mm and a depth of 20 mm, while maintaining good pitch accuracy between the coaxial cables of the flat cables. It was possible to pass through without damaging.

[Example 4] Flat cable 108
A dielectric layer made of PFA having a thickness of about 25 μm is provided on the outer periphery of a central conductor made of a conductor (single wire) having a diameter of 25 μm, and a conductor wire having a diameter of 20 μm is wound around the outer periphery of the dielectric layer to form an external conductor layer. A horizontal shield layer is formed, an outer conductor layer is provided with an outer jacket having a thickness of about 20 μm, and 620 ultrafine coaxial cables having an outer diameter of 0.155 mm and a cable pitch of 0.2 mm are formed by EPTFE. A flat cable 108 was prepared by fixing only one side of the formed laminate sheet having a thickness of 35 μm.

  The flat cable 108 can be passed through a hinge having a through hole having an inner diameter of 5.5 mm and a depth of 20 mm without damaging the flat cable 108 while maintaining good pitch accuracy between coaxial cables. It was.

[Example 5] Flat cable 109
A dielectric layer made of PFA having a thickness of about 52.5 μm is provided on the outer periphery of a central conductor in which seven conductors having a diameter of 20 μm are twisted, and a conductor wire having a diameter of 30 μm is wound around the outer periphery of the dielectric layer. A laterally wound shield layer is formed as a layer, an outer conductor layer is provided with an outer jacket having a thickness of about 35 μm, and 20 micro coaxial cables having an outer diameter of 0.31 mm and a cable pitch of 0.4 mm are provided. A flat cable 109 was prepared by fixing only one side with a 35 μm thick laminate sheet formed of EPTFE.

  This flat cable 109 can be passed through a hinge having a through hole with an inner diameter of 2.0 mm and a depth of 20 mm without damaging the flat cable 109 while maintaining good pitch accuracy between coaxial cables. It was.

  Although the embodiments and examples of the present invention have been described above, the flat cables 101 and 102 according to the present invention are flat cables in which a plurality of coaxial cables 10 are arranged in parallel. The diameter is 0.15 to 0.35 mm, and at least a part of the outer periphery (outer jacket 14) of the coaxial cable 10 is fixed to a laminate sheet 50 made of porous polytetrafluoroethylene (EPTFE). It is configured to be able to pass through a 5.5 mm through hole.

  Accordingly, the flat cables 101 and 102 are excellent in flexibility and flexibility because the plurality of coaxial cables 10 are fixed to the laminate sheet 50 made of porous polytetrafluoroethylene (EPTFE). , 102 can be passed through even a very small through-hole by bending or rounding in the longitudinal direction (axial direction). As a result, the flat cables 101 and 102 can be passed through the hinge hole of the portable telephone, and can be used for connection of the portable telephone. Furthermore, it is possible to maintain a good pitch accuracy between the coaxial cables 10 and easily and reliably perform complicated and troublesome electrical connection.

  Further, the flat cables 101 and 102 according to the present invention are characterized in that at least 20 coaxial cables 10 are included. As a result, the flat cables 101 and 102 can be passed through extremely small through-holes while maintaining good pitch accuracy between coaxial cables by bending or rounding, and more sophisticated and complicated wiring and connection are required. Even electronic devices can be used.

  The flat cables 101 and 102 according to the present invention are characterized in that the laminate sheet 50 has a thickness of 30 to 150 μm. Accordingly, the flat cables 101 and 102 can be excellent in flexibility and flexibility, and also in durability.

  The flat cables 101 and 102 according to the present invention are characterized in that the fusion layer 52 is made of a tetrafluoroethylene / hexafluoropropylene copolymer (FEP). As a result, the flat cables 101 and 102 can fix the coaxial cable 10 (outer sheath 14) to the laminate sheet 50 by thermal fusion, and further, laser processing is performed on a part of the laminate sheet 50 after fusion fixation. It is also possible to peel off that part.

  The scope of the present invention is not limited to the above-described embodiments and examples, and can be applied to various other embodiments as long as they do not contradict the description of the claims. It is also possible to further improve the use and function of the flat cable by performing terminal processing on the flat cable according to the present invention.

  The flat cable according to the present invention can be applied to the field of automobiles as well as used in electronic devices such as mobile phones and personal computers.

It is a figure which shows the coaxial cable 10 and the laminate sheet 50 which comprise the flat cable which concerns on this invention, respectively. It is sectional drawing which shows the flat cables 101 and 102 which concern on this invention. It is sectional drawing which shows the state which bent the flat cable, and the rounded state, respectively. 3 is a plan view showing an example of a terminal structure at one end of the flat cable 101. FIG. It is a top view which shows the example of the usage condition of the flat cable 101c. 6 is a plan view showing a state where the flat cable 101c1 is passed through a hinge 80. FIG.

Explanation of symbols

10 coaxial cable, 11 center conductor, 12 dielectric layer, 13 shield layer, 14 jacket, 50 laminate sheet, 51 base layer, 52 fusion layer, 101, 102 flat cable

Claims (4)

In a flat cable configured by arranging multiple coaxial cables in parallel,
The outer diameter of the coaxial cable is 0.15 to 0.35 mm,
At least a part of the outer periphery of the coaxial cable is fixed to a laminate sheet made of porous polytetrafluoroethylene having a fusion layer,
A flat cable configured to be able to pass through a through hole having an inner diameter of 2.0 to 5.5 mm. The flat cable according to claim 1, wherein at least 20 coaxial cables are included. The flat cable according to claim 1 or 2, wherein the laminate sheet has a thickness of 30 to 150 µm. The flat cable according to any one of claims 1 to 3, wherein the fusion layer is made of a tetrafluoroethylene / hexafluoropropylene copolymer.

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